The present invention relates to a vehicular seat having an improved headrest mounting structure.
This type of vehicular seat in the past has been disclosed in U.S. Pat. No. 5,378,043. In this vehicular seat, when the vehicle is subjected to a rear-end collision, an inertial force causes the upper body of the passenger to push a pressure-receiving member within the seat back relatively toward the rear of the vehicle, this force being used to move the headrest toward the front of the vehicle and upward with respect to the vehicle, thereby effecting an early restraint of the passenger""s head.
In this vehicular seat, however, the configuration is such that, when the upper body of the passenger presses the pressure-receiving member of the seat back in more than a certain amount, the headrest always moves forwardly upward, providing restraint even when the restraint by the headrest is not needed.
It is an object of the present invention to provide a vehicular seat in which a headrest is allowed to move only when an early restraint of passenger""s head is needed.
An aspect of the present invention to achieve the object is vehicular seat comprising a seat back, a headrest mounted to the seat back and movable at least forward from a set position, a linking mechanism provided to the seat back, and configured to transmit an inertial force due to a load by a passenger""s body acting on the seat back, causing the headrest to move forward, a detector configured to perform a detection of contact of the passenger""s body with the headrest, and a canceler configured to cancel transmission of the inertial force by the linking mechanism when contact of the passenger""s body with the headrest is detected by the detector.
According to this aspect of the present invention, the headrest is moved forward in response to an inertial force that is transmitted by the linking mechanism when the load of the passenger""s body acts on the seat back due to a vehicle collision or the like, thereby enabling quick restraint of the head of the passenger. In addition, when the detector detects that the passenger""s body has come into contact with the headrest, the canceler can cancel the transmission of inertial force by the linking mechanism. Thus, it is possible to block forward movement of the headrest, so that when a passenger sits in a seat in a relaxed condition, for example, the headrest is not needlessly caused to move forward, thereby improving comfort.